1. Fields of the Invention
The present invention relates to a diagnostic device for vehicles, and more particularly, to a diagnostic device for checking throttle valves of a vehicle, and a cleaning device is connected to the throttle valves to clean the throttle valves.
2. Descriptions of Related Art
The operation of throttle valves of early vehicles comprises a cable connected between the throttle valve and the acceleration pedal, the cable is pulled to open the throttle valves when the acceleration pedal is pushed. For the modern vehicles, a sensor is used to detect the operational status of the throttle valves, and the detected information is sent to the engine control unit to precisely control the timing of the opening of the throttle valve to provide better fuel consumption features.
For protection the environment, an exhaust gas recycling system is developed to recycle the exhaust gas and the exhaust gas is guided back to the intake system to be burned again when the vehicle is idling. Carbon is accumulated and attached on the valve and affects the performance of fuel consumption. Another system called positive crank ventilation is able to guide the mixture of gasoline and air in the crank box into the engine to be burned again, and this may also cause the accumulation of carbon. Therefore, the timing for cleaning the accumulated carbon particles on the valves is important to keep the engine in a satisfied status. The conventional cleaning device is connected to the valve to be cleaned and after the cleaning processes of the cleaning device are completed, the cleaning device is removed and the engine needs to be put on idling status for ten minutes. However, there is no way to check the engine is in its default status after cleaning.
The present invention intends to provide a diagnostic device for checking throttle valves of a vehicle so that the maintainers can use a cleaning device to clean the throttle valves. By checking the intake air and the exhaust, the diagnostic device detects whether or not the engine is in its default status after cleaning.